Sims 4 help!! saves

Hi Simmers, 

Please could someone help me! 

Okay so I have multiple different families that I play, they are all intertwined somehow whether that be brothers, sisters etc. Now a few months ago I had them all under one save and would dip in and out of the different families. However, for some reason I started saving them all seperately because I thought that was the best thing to do. However, for instance one daughter is a teen in one save but when i go into the other family in the other save she is a child. 

All I want to know is if there is any way to get the 4 seperate families as they are now, back under one save file? 

PLEASE PLEASE HELP!!! 

Thanks Simmers!